The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Modern day braking systems used on motor vehicles such as passenger cars and trucks often employ a Primary Brake System (“PBS”) and a Secondary Brake System (“SBS”) which are hydraulically connected in series. The PBS provides the main means for generating brake pressure to the brake calipers associated with the four wheels of the vehicle. The PBS, does this while constantly monitoring the hydraulic fluid that it applies and the pressure it generates, internal to the PBS itself.
The SBS often forms a portion of an Electronic Stability Control System (“ESC”). The ESC system is able to independently control hydraulic pressure applied to the brake calipers of at least two wheels of the vehicle, often the front right and front left brakes calipers, in response to detected braking conditions (e.g., emergency evasive braking maneuver), with a goal maintaining control of the vehicle. The SBS also forms a backup braking system which is able to hydraulically control the brake fluid applied to at least two brakes of the vehicle in the event that a failure occurs in the PBS.
The growing interest in autonomous vehicles has also added the requirement of a validation mechanism to check that the SBS is functioning normally, even while the PBS is functioning normally, to ensure the redundancy of the overall braking system. Ideally, this validation mechanism should be implemented with minimal additional component parts being introduced into the vehicle's braking system and without unduly complicating operation of the PBS or the SBS. Moreover, the validation mechanism should operate transparently to the user so that a validation check can be automatically performed by the braking system.